Rifle-sight.



W. B. BURTON.

RIFLE SIGHT.

APPLICATION HL'ED FEB. 21, I913.

Patented June 8, 1915.

Inventor.

Witness es THE NORRIS PETERS CO4, PHOT0-L|THO.. WASHINGTON. u. U.

WILLIAM BURTON BURTON,

0F ANNANDALE, NEW SOUTH WALES, AUSTRALIA.

RIFLE-SIGHT.

Application filed February 21, 1913.

To all whom it may concern Be it known that I, l/VILLIAM BURTON BURTON,a subject of the King of Great Britain and Ireland, residing at Kenton,Kentville avenue, Annandale, in the State of New South WVales,Commonwealth of Australia, have invented certain new and usefulImprovements in Rifle-Sights, of which the following is a specification.

This invention relates to the rear-sighting devices of rifles. In thesearms the said de .vices usually consist of a ladder pivotally vmountedupon the top of the barrel and arranged to lie flat thereon when not inuse and to be erected into a slightly angular or into a verticalposition when required, and a cross-bar provided with a sighting notchor peephole slidably mounted upon the said ladder. The latter isgraduated to indicate the correct position of the cross-bar for a givenrange, but owing to its limited length the graduation marks thereon tobe clear and distinct must be limited in number and indicate ranges ofconsiderable difference. Further, with this form of sight it isnecessary that the particular range at which it is intended to shootshould be made known to the marksman in order that he may correctlyplace the cross-bar, and the effecting of such adjustment generallynecessitates the removal of the rifle from the shoulder. The'lack ofcapability of fine adjustment is a drawback at all times, and the delayin adjustment of the cross-bar might in war he a matter of considerablemoment.

In the peephole form of sight the distance of the sighting aperture fromthe eye of the marksman is fixed, and consequently the field of visiontherethrough varies as the range and the particular object aimed at isseen in a field of different area at each range.

At long ranges the area of the field is very great compared to thetarget, clearness of definition of the latter being therebypreiudicially affected.

Rifle sights as at present in use are relatively short and theirfunction is merely to elevate the peep hole and not to change therelative distance of said peep hole fromythe eye. This invention has asits primary object to arrange a rational relation between the elevationof the peep hole or sighting aperture and its distance from the eye withthe object of obtaining a constant area of Specification of LettersPatent.

the

Patented June 8, 1915. Serial No. 749,808.

field of vision as seen through the peep hole for the object aimed at.In the ordinary peep hole sight the distance of the sighting aperturefrom the eye of the marksman is practically fixed, consequently thefield of vision therethrough varies as the range and particular objectaimed at is seen in a field of different area at each range.

The object of the present invention is to provide a simple rear sightingappliance of simple construction readily adaptable to any ordinary riflebarrel, and adapted to give quick and sure adjustment, in whichvariation of the elevation of the sighting aperture is effected bylongitudinal movement thereof, and which is so constructed and arrangedas to offer a field of vision through the sighting aperture ofpracticallythe same area at all ranges.

I will now refer to the accompanying drawings illustrating theconstruction of rifle sights according to this invention.

Figure 1 is a perspective view of part of a rifle with the applianceattached. Fig. 2 is a cross sectional elevation of the ladder andsliding element. Fig. 3 is a perspective view on a larger scale of thesliding element so constructed that the member carrying the sightingaperture is slidable laterally thereon by means of rack and pinion gear,thereby providing a wind-gage. Fig. 4 is a transverse sectionalelevation of Fig. 3. Fig. 5 is a longitudinal sectional elevation of thesame. Fig. 6 is a plan view of the same, and Figs. 7 and 8 arediagrammatic views which will be hereinafter described.

The barrel 8 of the rifle has affixed to it the ladder 9 which consistsof a strip of metal having its upper surface inclined upwardlv towardthe muzzle end 10. A fixed rear sight 11 is provided for obtainingalinement at ranges known as point blank, 6. under 300 yards, and toenable the foresight (not shown) to be seen through the notch in thesaid rear-right the ladder has a groove 12 cut in its upper surface.which groove also reduces the quantity of metal and tends to lightness.The ladder 9 has a pair of outwardly turned flanges 13. 13.

The sliding element consists of a carriage 14 having a pair of inwardlyturned flanges 15. 15. by means of which it engages the ladder 9.Pivoted to the said carriage is the member 16 capable of being erectedto a element is in this case pierced vertical operative position andalso capable of bein reclined to a horizontal inoperative position asshown in dotted lines in Fig. 5. 1n the said member 16 are formed thepeepsight apertures 17 and 18. V

In practice I have found that very good results are obtainable by theuse of a sighting aperture of such configuration that the planes of itsaxes (particularly the vertical axis) are readily determinable, and themost suitable configuration is that of a diamond illustrated in thedrawings. It is to be understood however that the type of aperture isoptional as some marksmen may have a preference for the ordinarycircular aperture or for other types, though the use of the diamondshaped aperture or its equivalent is a safeguard against rolling.v therifle,

the vertical axes of the sighting aperture and of the target beingreadily brought into al-inement.

At the top of the member 16 a notch sight may beprovided toruse inobtaining correct alinement of the rifle when shooting at a rangeoutside the effective range of the rifle.

The ladder 9 may be of any convenient length, and suitable'markings areprovided ,uponlits face to indicatethe correct position'of theslidingelement for a given range. As the sliding element or carriage '14 iscaused to slide toward the muzzle, which movement is for shooting atgreater range, its distance from the eye of the marksman increases whileits distance from the foresight decreases, and consequently the heightof the s ghting aperture above the barrel required to bring the saidaperture the foresight and the object aimed at into line, is not sogreat as is necessary with a fixed rear sight. Further, thecomparatively great length of the ladder renders possible clear anddistinct graduation for ranges of small relative variation. rorexamplewhile an ordinar ladder sightis graduated in ranges of not lessthan 50 yards variation it is possible with my invention to graduate theladder and accurately'adjust the sliding element for ranges of 5 yardsvariation or even less.

To provide for shooting at ranges exceeding say 900 yards without undulyincreasing the length of the ladder 9, the ranges up to that distancemay be marked on one side of the surface of the ladder and those inexcess thereof on the other side. The sliding with two sightingapertures one positioned above the other, the marksmen using theupperone for the greater ranges. I

Theoretically the length of the ladder is limited only by the length ofthe rifiebarrel, but in practice I. find that a lengthof about allpositions. If therefore a: rifleman acquaints himself by practice withthe appearance or proportion in the field of vision (as seen through thesighting aperture) of an object of known size he may when desiring toshoot at an unknown range so adjust the carriage that this proportionis' obtained, with the reasonable assurance that the carriage is in thecorrect position on the ladder to give the elevation required for theparticular range, and it is then unnecessary to referto the graduatedscale' as' the shot may now be fired in the ordinary manner. It isnecessary however that the size of the target should be known, and thatthe marksmans eye when he is adjusting the carriage should be in thecorrect position for shooting.' The sighting aperture may however bemade of such dimensions that the field of vision therethrough willembrace only the target, the necessity for judgment of the proportionatesize of the target to the field being thereby obviated If desired,however, the range adduced from the aforesaid adjustment may be readfrom the graduated scale on the ladder. It is considered, however, thatthe appliance used in this manner would not be effective at a greaterrange than say 800 yards, as beyond that human eyesight would probablynot be sufficiently dependable.

The diagrammatic views, Figs. 7 and 8 illustrate in exaggerated form'the eflect' referred to. It will be noted that the target 20 is the samesize and that the eye 21 of the marksman is in the same position in eachcase. will also be noted that the range, e., the distance between 20 and21, is very much greater in Fig'.' 7 than in Fig. 8, and, in order thatthe vision through the. sighting aperture 17 (or 18") in member 16 mayin each case embrace only the target, that the said member is muchcloser, to the eye in Fig. 8 thanin' Fig. 7. If the correct position ofthe member 16 and consequently or the carriage 142 is thus deter- 'minedaperture- 17 ...a special range-finding aperture, and this aperturewould preferably consist of a vertically elongated slot such as 19 whichconfiguration eliminates side field and conduces to clearness ofdefinition.

It is to be understood that the determination of range requires practiceand familiarity with the rifle, just as with ordinary sighting devicesthese attributes to proficiency are necessary.

The appliance is characterized by simplicity and lightness there beingpractically only two pieces; also by unobtrusiveness and stability, andit does not interfere with drill movements. It can be attached to anyrifle at a minimum of cost, can be affixed at original sight-base onrifle and enables perfect focusing to be obtained through the peepsight,the field of vision being the same at all ranges.

In certain circumstances it is desirable to use a wind-gage whenshooting, and when this is required I so construct the carriage and themember carrying the sighting aperture or apertures that the latter iscapable of sliding laterally on the former, such movement being effectedby rack and pinion gear. This construction is illustrated in Figs. 3 and4. The sliding carriage 1 has a channeled lateral extension 22 withinwhich slides a toothed rack 23 toone end of which is attached theapertured member 16. A pinion 2% engages the said rack and is rotatableby means of the disk 25 having a graduated dial on its face, and apointer 26 is provided so that the extent of the lateral displacement ofthe member 16 may be accurately and automatically registered.

The attachment of the wind-gage to a sighting appliance constructed andoperating as herein described has advantages, inasmuch as the lateraldisplacement of the wind-gage is the same at all ranges when shootingunder the same physical conditions.

Obviously the greater the range the greater must be the windage allowed,that is to say the lateral angularity of the rifle barrel must beincreased as the range is increased. As however the member carrying thesighting aperture is moved proportionately closer to the foresight asthe range increases so the sighting base is proportionately reduced andthe horizontal angle between the line of vision and the rifle barrel isautomatically proportionately increased without readjustment of thewind-gage.

The determining of the relative proportions of the sighting orifice andscale is a simple mathematical proposition and depends upon the relativeproportion of the sighting aperture, the normal target, say a six-footheight, and the length of rifle barrel together with the height of theforesight. It will be readily understood that with these particularsdefined the rear sight may be moved longitudinally of the bar accordingto the difference of range and so that the aperture therein will at thedifferent ranges comfortably inclose the normal target.

If an observation is taken at a short range, say two hundred yards andat a long range, say nine hundred yards the height of the ladder 9 atthe two points found may be calculated with reference to the length ofbarrel, height of fore-sight and muzzle velocity. The height of theladder in any intermediate points is then determined by a straight linejoining the two fixed points and the intermediate gradutions are markedby observation of the target through the aperture, care being taken toalways observe a standard size of target in the setting of the scale.

In respect to the automatic adjustment of the windage, it is obviousthat the base line, that is, the distance between the movable back-sightand the fore-sight is shortened as the range increases, consequently thewindage base line automatically varies as the sight is moved along thebarrel. For example, suppose we set the rear sight with five pointswindage. It is obvious that if the setting is not changed when the sightis moved forward along the barrel the angle of lateral deflection of thebarrel is automatically increased or decreased.

In practice it is found that the automatic adjustment is correct withina small fraction and that the marksman having obtained by trial orjudgment the correct windage for any given range has no need to altersame for other ranges under the same conditions. I

What I claim and desire to secure by Letters Patent is 1. A rifle sight,comprising, a graduated plane arranged longitudinally of the riflebarrel and inclined in relation thereto, and a member slidably mountedon said inclined plane and having a sighting aperture therein, saidplane being so inclined and graduated as to effect the proper elevationof the rifle barrel at the distance of the target when the area ofvision as seen through the sighting aperture is maintained uniform.

2. A rifle sight, comprising, a graduated plane arranged longitudinallyof the rifle barrel and inclined in relation thereto, a member slidablymounted on said inclined plane, a member having a sighting aperturesupported on said sliding member and adapted to be adjusted laterallythereon, said plane being so inclined and graduated as to efl ect theproper elevation of the rifle barrel at the distance of the target whenthe area of vision as seen through the sighting aperture is maintaineduniform and to effect a proportionate change of lateral inclination ofthe rifle barrel for windage on a change of elevation.

3. In a rifle sight, :an inclined guide Way of FT-shape 1n cross sectionhavlng'range 'graduations thereon; a carriage slidably mounted .on thetop of said guide Way and having inturned edge flanges embracing thehead thereof, and a leaf member mounted on said carriage and having asighting aperture therein.

4. improvements in rifle sights comprissing in combination an inclinedplane onthe rifle having .a longitudinal groove or depression therein,an element slidable longiapertures is or are formed, and a fixed rearsight arranged in allnement With said longitudinal groove.

In testimony whereof I affix my signature 1n presence of two Witnesses.

WILLIAM BURTON BURTON.

Witnesses:

YVM. NEWTON, v

CHAS. HA'rrroN (fopiesof this patent may be obtained for five centseach, by addressing the Commissioner of Patents,

Washington,

